Over the past 20 years there has been a reported 300% increase in the number of Americans who report that they few or no close confidants. This is not only upsetting, but now an analysis of a total of 23 scientific studies reveal just how physically sick loneliness can actually make you.

According to a 2016 study published in the British medical journal, Heart, those who suffer from “poor social relationships” experienced a 29% greater risk of heart disease, and 32% greater risk of stroke.

These statistics equalize loneliness and social isolation with other well-known risk factors for cardiovascular disease such as anxiety and job strain. These statistics also surpass the cardiovascular risks of physical inactivity and obesity. Lead researcher Nicole Valtora of the Department of Health Sciences, University of York, England reports that “interventions to prevent coronary heart disease and stroke should take loneliness and social isolation into consideration.” She went on to say that such interventions could be relatively inexpensive to implement, especially when considering that the cost of ignoring cardiovascular disease factors totaled $193 billion in 2015.

However, it is important to note that loneliness and social isolation are not always linked. It is possible to feel lonely in a crowd, or to be alone and feel content. It is when your experience is negative, you are not happy with your social interactions, or if you’re grieving a loss will be when your well-being is at risk.

Valtora’s studies involved 181,000 people living in the U.S., Europe, and Japan, the data excluding those who identified as lonely, but had already been diagnosed with cardiovascular disease. Participants were tracked for between 3-21 years, and it was found that among these people there were 4,628 heart attacks or related events and 3,002 strokes. Further, the data showed that age was not necessarily a factor, and there was no significant difference between men and women.

A separate study performed in 2015 by Brigham Young University researchers concluded that both actual and perceived isolation were associated with early death. Social isolation corresponded with a 29 percent greater risk of premature death, loneliness corresponded with a 26 percent greater risk, and living alone corresponded with a 32 percent greater risk. This same data also determined that social isolation and loneliness threatened longevity as much as obesity did. Interestingly, in 2010 this same team of Brigham Young researchers were also involved in a study that concluded that loneliness is as bad for your heart as smoking 15 cigarettes a day.

According to Brigham Young researcher Julianne Holt-Lunstad what can be done to mitigate the cardiovascular risk of loneliness and social isolation is to nurture close relationships and seek to develop a “diverse set of social connections”. A key advantage in elderly populations often occurs within the setting of a long-term care facility where residents may have previously been isolated due to physical or cognitive impairments, but now enjoy a richer social and activity structure with their peers.